1. Field of the Invention
The present invention relates generally to lighting effects fixtures, and in particular to an improved rotatable gobo holder assembly which removably retains the rotatable gobo holders to a rotatable gobo platform.
2. Background Information
Prior art U.S. Pat. No. 6,601,973 (the '973 Patent) shows a removable, rotatable gobo holder assembly which attaches a removable, rotatable gobo holder into at least one of several apertures within a rotatable baseplate. The rotatable baseplate includes a spring retainer which holds multiple removable gobo holders to the base plate to interact with gearing assemblies. The '973 Patent assembly requires each of its relative pieces to fit in a very coordinated manner. The coordinated manner of attachment allows each gobo holder to be removed and replaced, causes each gobo holder to engage a single gear assembly and thereby rotate its gobo caused by the rotation of the single gear assembly, and for the entire rotatable baseplate to be held and be rotatable to move one of its several gobos into and out of a light path in a controlled manner.
The spring retainer fixed to the rotatable baseplate of the '973 Patent assembly is meant to removeably mate with the gobo holders so the gobos can be removed and replaced from time to time. However, each time the '973 Patent's spring retainer is pulled back to allow a gobo holder to be replaced in an aperture of the baseplate, the spring retainer loses tensioning strength. Over time the spring retainer will stop providing enough strength to adequately hold the gobo holders in place within the apertures in the baseplate.
As the single spring retainer attached to the rotatable baseplate loses tensioning strength, it will stop retaining one or more of the removable gobo holders in a fixed position and the operational capacity of the entire assembly will diminish because the assembly will only hold 5 out of 6 gobos and then 4 out of 6 gobos, etc. In order to address this problem, then the entire assembly must be removed and the baseplate along with its fixed spring retainer must be replaced. This is often a difficult chore since the entire lighting fixture may be held hundred's of feet in the air above a stage or otherwise out of reach.
Further, in the prior art rotatable gobo holder assembly of the '973 Patent, each gobo holder is required to have a flange around its circumference. The flange must mate with the spring retainer in a particular way so that all of the parts carefully fit in place and in turn mate. This includes the gobo holder fitted within the aperture of the baseplate, and the flange fitted within the spring retainer and the gear assemblies fitting together to allow the forces of rotation to be translated throughout.
Another prior art rotatable gobo holder is found in U.S. Pat. No. 7,370,990 and US Patent Publication No 20080175004 (the '990 Structure). In the '990 Structure, “lamellas” or tabs attached to the rotatable gobos fit underneath flexible fingers of a central holding means fixed to a carrier disc. The '990 Structure has similar problems as the '973 Patent structure. Although the '990 Structure has less of a guide mechanism to fit the rotatable gobo holder onto the carrier disc and thereby engage the main gear assembly, the flexible fingers are susceptible to being stretched and losing tensioning strength thereby requiring replacement of the entire carrier disc assembly.
In application, there have been several implementations of rotatable gobo holder assemblies where the rotatable gobo holders are held in place by flanges or tabs engaging a spring retainer or flexible fingers fixedly attached to the rotating carrier. These include Martin Professional Mach 2000 series, ROBE Lighting's, Color Spot Series Products, and Elation Lighting's Model Year 2007 and earlier, Power Spot 700 Products. These products are generally called moving head light fixtures.